1) Field of the Invention
This invention relates to antidiarrheal compositions with loperamide hydrochloride contained therein, and more specifically to antidiarrheal compositions which enhance the antidiarrheal efficacy of loperamide hydrochloride yet contain less loperamide hydrochloride to reduce development of its side effects.
2) Description of the Related Art
Of gastrointestinal symptoms, the most frequent is diarrhea. Diarrhea is known to be induced by an increase of peristalsis due to inflammation of the enteromucosa by a cause such as infection by a virus or bacterium, emotion or psychogenesis, overeating or the eating of spoiled food or the like.
If taken into consideration that diarrhea is a biodefense reaction for earlier excretion of a substance toxic to the living body, early recourse to the use of an antidiarrheal should be avoided.
Diarrhea may however result in serious dehydration unless proper treatment is applied. Administration of an antidiarrheal agent as early as possible is desired as a symptomatic therapy in such a case.
As symptomatic therapeutic agents for diarrhea, chemotherapeutic agents, astringents, atropine preparations and the like have been used to date depending on their causes. Further, opium and morphine are also known to induce spasticity of the intestinal smooth muscle and peristaltic ataxia to provide antidiarrheal effect.
However, morphine has the potential danger of addiction such as dependence due to central effects. It has therefore been considered necessary for many years to separate central effects and intestinal effects from each other in the use of morphine as an antidiarrheal agent.
Loperamide hydrochloride, which has been developed recently as an antidiarrheal agent, selectively acts on the intestinal tract to suppress peristalsis, and to reduce the secretion of water and electrolytes from the intestinal tract and promotes their absorption. At the same time, loperamide hydrochloride exhibits strong antidiarrheal efficacy and shows low central effects. Loperamide hydrochloride is therefore said to be an antidiarrheal agent having a broad safety zone. Capsules and powders containing it are already on the market.
Although loperamide hydrochloride has relatively few side effects it is not completely free of them. It may lead to oversensitivity such as efflorescence, urticaria or itching; symptoms such as drowsiness, hypotonicity and mydriasis in the central neural system; and symptoms such as abdominal distension, abdominal discomfort, nausea, vomiting, anorexia, unpleasant oral feeling and abdominal pain in the digestive system. It is therefore preferable to reduce the dosage, especially for infants.
It has therefore been desirable to develop a loperamide-hydrochloride-containing antidiarrhea composition which, even when the dosage of loperamide hydrochloride is small, still provides positive diarrhea control but gives reduced side effects.